[ODE] what a drag

[Nate W]

On Fri, 4 Apr 2003, Pierre Terdiman wrote:

> > The part about computing the cross section sounds hard, unless the geoms
> > are all spheres.  Anyone know of a simple and/or fast way to do that for
> > boxes at arbitrary orientations?
> 
> Isn't it the same as in the old code from Dieter Schmalstieg, to compute the
> screen projection area of an arbitrary box......... ?

I'd never heard of him 'til now, but I think you're right.  If anyone else
is interested, here's an URL:

http://www.acm.org/jgt/papers/SchmalstiegTobler99/

I just had an alternate idea though... Could one create "drag matrix" for
a geometry object, such that multiplying a velocity vector by that matrix
would result in an approximate (if not highly accurate) drag force vector?  
I realize that I have just gone one step beyond my real understanding of
linear algebra, so please be gentle if this is totally wrong. :-)

-- 

Nate Waddoups
Redmond WA USA
http://www.natew.com